INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Mesoporous aminopropyl-functionalized hybrid thin films with modulable surface and environment-responsive behavior
Autor/es:
A CALVO; P C ANGELOMÉ; V. M. SÁNCHEZ; D. A. SCHERLIS; F. J. WILLIAMS; G.J.A.A. SOLER-ILIA
Revista:
CHEMISTRY OF MATERIALS
Referencias:
Lugar: Washington DC; Año: 2008 p. 4661 - 4661
ISSN:
0897-4756
Resumen:
A first study of the behavior of amino functions in mesoporous hybrid thin films M1-x(Si-(CH2)3NH2)xO2-x/2 (M ) Si, Ti, Zr; 0.05 e x e 0.2) with accessible Im3jm- or Fm3jm-derived poremesostructures is presented. An XPS study of surface nitrogen species shows two different sites corresponding to amino and ammonium groups. The ratio of these species changes with pH and is related to the nature of M, suggesting that the interaction between the organic functions and the surface M-OHgroups can be tailored to tune the surface acid-base behavior. Density functional theory (DFT) calculations were used to rationalize the XPS observations showing that -NH3 + functions irreversibly transfer a proton to neighboring M-O- surface groups. The acid-base surface properties can be further modified by adding a phosphonate “capping” on the M surface sites. Our findings have a series of interesting implications in surface functionalization: attachment of biomolecules to surfaces, design of perm-selective or philicity-selective membranes, or design of catalysts that show a well-defined organic reactive function near surface hydroxyl groups.